Comparison of methods of stress-strain state estimation in the upset of a cylindrical workpiece

The paper reviews the methods of stress-strain state estimation in the upset of a cylindrical workpiece developed by L. Prandtl, G.Ya. Gun and V.L. Kolmogorov. These methods were compared using numerical simulation by DEFORM-3D software and experiment. The test task was the upset of a cylindrical workpiece made of lead with the initial height to diameter ratio of 0.53. The final relative strain of the workpiece was 0.18. It was found that the engineering methods (those of L. Prandtl and G.Ya. Gun) allow to obtain the lower boundary of the upset forces. V.L. Kolmogorov’s method belonging to the class of variational methods, and computer modeling in DEFORM-3D give the most close agreement to experimental results. At the same time it is to be noted that the variational methods in pure form are highly labor-intensive in the pre-processing of even simple tasks and cannot be used to solve practical problems in industry. Computer modeling in DEFORM-3D allows to get the desired results in a short time, and the process of forming analysis is facilitated by the visualization of the problem statement and its solution process. A significant drawback of computer simulation is the high software cost.